Semi-mechanical telephone-exchange system.



. A. M. BULLARD.

SEMI-MECHANICAL TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED m. s. 1901.

1 ,1 61 ,608. Patented Nov. 23, 1915.

9 "HTS-SHEET I.

A. M. gunman. I SEMI-MECHANICAL TELEPHONE EXCHANGESYSTEM.

APPLICATION I'll-ED IE!- 5. I907.

1,161,608. Patented Nov. 23, 1915.

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A. M. BULLARD.

SEMI-MECHANICAL TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. 5. 1907.

1 ,1 61,608. Patented Nov. 23, 1915.

9 SHEETS-SHEET 5- Nb Rf Q comm "Am-AP" CO.- WAIMINGTON, D. C.

A. M. BULLARD.

SEMI-MECHANICAL TELEPHONE EXCHANGE SYSTEM.

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COLUMIIA PLANOGIAN' O. WAIMINWON. 0' C.

A. M. BULLARD.

SEMI-MECHANICAL TELEPHONE EXCHANGE SYSTEM.

Amlcmou FILED m. s. 1902.

1 1 61 ,608. Patented Nov. 23, 1915.

9 SHEETS-SHEET 1.

%% APYQMMLZZ CBLUHIIA MIA? CO" WAIHINOTON, f C.

M E T 5 VI 3 E G N A .H .C ox Dn ME LN L0 UH B E IL E M IL AA C N A H C E M l M E 5 APPLICATION FILED PEI. 5.1901. ,608.

Patented Nov. 23, 1915.

O SHEETS-SHEET 8.

A. M. BULLARD.

SEMI-MECHANICAL TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. 5. I901. 1,161,608. A

Patented Nov. 23, 1915.

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COLUIIIA MIA!" ,WAIMIW. D. E.

STATES BilENTOFFIGE.

sniannrm. 'B'ULLARD, or- NEW YORK, N. 'Y.,' Assrenon 'ro wns'rsnu nnnc'rmc i COMPANY, oscmcaeo, ILLINOIS,A conrons'rxon or nmaroxs.

new-and useful Improvementin 'Semi-Me-' ch'anical Telephone-Ilxcharige Systems, of which the following is a full, "clear, concise,

and exact description.

My invention relates to'a' telephone exchange system wherein the operator a't the' central oilice answers the call of a subscriber in-the usual way by uniting her connecting circuit with such subscribers lme, and'me chanlcal switching mechanism completes the connection by uniting the connecting circuit with the called line.

.The object of my invention :is-to provide an improved system which will'be veryefli-j cient and reliable in operation and'make possible great speed and lishing connections.

for extending the circuitsof callin lines,

and automatic "switches for extending .the-

connecting circuits to the wanted lines. The automatic switches, of which there are usually several operatedin succession throu h trunk lines for each connection, may

associatedavith the connecting circuits.

In accordance with one feature of my in- VfllltiOIlrhfl automatic ringing apparatus is provided in such a system as'that described abovevinassociation withv a final selector. switcher connector and made operativethe, proper character is, applied to such line to signal thesubscriber thereof." In accordance with'j'this feature there is provided one terminal or set of terminals on the final selector-,foneachsubstation onthe line, and

"the testterminals of suchtlineiare connected Specification of Letters Patent.

Application m d February 5, 1 907. Se1'1a1Nc.355,886.

precision in estab e, as in the 'system herein described, controlled by operators sending mechanisms SEMI-MECHANICAL TELEPHONE-EXCHANGE sYs'rEM.

atent Nov. 23, 1915.

together with a resistanceeincluded' in the conductor between certain terminals. In the case of four party lines, the line terminals of certain"subscr1bers are transposed with respect'to those of other subscribersof the same line. This arrangement, in association with certain relays and testing means associated with ,the final switch, enables the proper ringing current, preferably. positive or negative pulsating, to be applied to one side'of the subscribers line or the other upon connection being'made thereto.

Another feature of myinvention relates to a new'and improved arrangementof circuits and apparatus for controlling the operation of the selector switches. In accordance with this feature the controller operating magnet and-the selector operating magnet are energized by pulsating current, the two'magnets operating one after the other, and the extent of movement of the selector being'determined by a switch actu- In -a system to which my invention isap plicable connecting'circuits are provided at the central oflice with switches, preferably manually operable such as plugs and jacks,

by reference to the accompanying drawings,

which illustrates the preferred embodiment thereof, reserving-for the appended "claims I a statement of the parts, improvements and combinations which I ?consider novel with In the drawings Figures 1, 2, 8, 4, 5, 0 and '7 represent an arrangement of circuits and apparatus of a telephone exchange system embodying my invention; Fig. 8 represents a single-station" line-leading to terminals upon the connector shown in Fig. 4; Fig. 9 shows afour-party line with its-connector terminals arrangedfor selective signaling;

and Fig. 10v shows a private branch exchange and its trunk lines and connector terminals. Fig-11 shows a simplified arrangement of the apparatus associated with the primary selector which may be used in connection with primary selectors to which a the trunks from the-oiiice selector. terminating and originating in the same exchange 'may be connected. 1

In tracing the system the drawings should be considered in orderof Figs. 7, 6; 5, 1', 2, e, 4, s, 9, 10.

In a system of, for example, 100,000 lines, there may be provided ten oiiic'es, at each of which terminate 10,000 lines. .At each oflice .c'onnector has a capacity of 300 lines and enough connectors are furnished to handle thelcalls'fj forseaclrzgroup. The operator in an exchange answers a call in the usual way by uniting her connectin circuit with the line ofthe calling subscri er, and afteras- 'certaiiiing the numbenof the called part and.-.,the exchange where -thelin'e of suc party terminates, operates her sending appa-;, ratus, depressing the-key thereof which re resents the desiredofiice, and the thousan s, hundreds, tens-and units digit keys repre-m senting the numbereof the linewanted; .An: office selector forms the terminals ofthe connecting circuit referred to, and is operated. 11% mechanism controlled .by.. the actuated o ce key to unite the connecting circuit with an. idle trunk line leading to the desired office. Said trunk lineterminates atthe desired oflice in a (primary selector, which is a machine adapts tose lect an idle connector belonging to anyone of the 34; groups. a

,A translator is: provided in connection: with the sending outfit..; to,cause the thou-, sands and hundreds keys depressed toope erate the primer selector and pick out an idle connector 0 the-. group des red. The. first 300,,1ines in the exchange arenumber' 0000 te oaoa. These numbers wouldbe reached by pressing the nau ht. button of the thousands keys and the 1 or 2 button' of the hundredeskeys. .--There is a primary controller forming artof the sending outfity'which controls't etoperation of the-primary selector, .the two being operated :to other in series. The translator is provi cdwith three brushes. The first is asso ciated-with the thousands and hundreds keysand arranged to stop thetranslator at a-predetermine point to.cause' the second brush and the rimary controller, which are automatically' brought into circuit a when :the translator has stopped, to advance" the=.:primary fselector into P08161011, to connect with the desired'connector. The third brush has associatedv therewith an. auxiliary con-v troller,-'a'nd said brush, after the operation of the primary controller, automatically brings intoplavtheauxiliary controller,- which advances the brushes of the selected connector to the proper-hundreds zone of the three zonesof one hundred lines each of such connector. The depressed tens andunits keys are now brought successively into service, mechanism controlled thereby o crating the selected connector to-cause t e brushes-thereof-to unite withths terminals of thedesired line in the selected zone.

Lwillmowdescmbe in detail'the circuits and apparatus "employed! in 'connecting the subscriber No: 999 shown'in Fig. 1, whose line terminatesat ofiice A, with the llne of the subscriber .No. 1132, shown Fig. 8,

whose line terminates at exchange B.

The line of subscriber No. 999, Fig. 1, extends-in two-limbs 1, 2 from the substation to the central oiiice A, where the line extends through the usual line signal apparatus to the poles of a central battery. At the central 0 ce, the usual answering ack 3 is provided for the,line, the thimble 4 of said jack being connected with a. conductor 5 which leads throu h the usual cut-off relay to the free pole o a grounded battery 6. The operator is provided with an answering lu ird hit withthe ,calling line, the plug 7 and jack 3 constituting a manual connection switch. ,1 r

The link conductors 8, 9 of the operators connecting circuit lead from the ti 10 and ring 11,- respectively, of the answering-plug,

through the windings of the usual repeating coil 'betweenwhich-is bridged a battery 12 in the usual manner, to the line brushes of an ofiice-selectcr 13, Fig. 2, a supervisory relay being included in link conductor 9 between upon the closure of the "connection-switch, is

provided with an; armature connected with the free pole of, the-battery 17 ,the front contact of said"-'armatu're being connected with-a-conduotor 18 leading-through contacts of thesupervisory relays and the supervisory lamps to earth.

A ey- 19 is rovided in association with the conductors 0 of the connecting circuit, adapted, when operated, to connect the operators telephone set with the link conductors of the'connecting circuit, andalso to close a pair of contacts, 20,21, which control the placing of-the sending apparatus into condition to: serve the connecting circuit. The contact 20 is connected with-a conductor 22-which leads through a resistance 23 and s rings 24,- 25, associated with relay 26, to t e free pole of a grounded battery 27, Fig. 5, while-the contact 21 is connected with a conductor 28 which leads through the armature 29 and back contact of relay'30, windings of relays 31 and 26, through the armature 82 and back contact'of relay 33 to earth. Thus when key 19 is operated, the circuit 22, 28.15 completed tooperate relays 31 and 26.

Referring first to relay 31, its armature 3 1 is connected with a conductor 85 which leads through the contacts of a key 36 to conductor 18, and conductor 18 being connecteclby the armature of relay 16 with the free pole of with which to unite her connecting cuit, to separatesaid springs, the spring:42-

a with a, common wire- 9:45 leading, i-tothe send circuit 'with-lcommon wires battery 17. The front'eontact of the armaturej34 of relay 3l'is connected with a eonearth.. 'Therarmature29 of relay,30-is now opera-te'cl'. and disconnects the..key. 19-from I theJoircuitofthemagnets 31', 26, so'th'atthe v ope'ratohmayat any-subsequent time during 7 the process. of establishing the connection, or during the connection; listenin' on the circuitqwthout interfering with the sending apparatus. The resistance 23v in conductor .22 is forthe purpose-of preventing a shortcireuit'ofthe relay 30 when the armature .34 of relay 31, closes the branch throughwind-- ing 38rof--:relay.-3O from-'batteryz17. The relay 31 is also provided with armatures :89, 40. The armature 89I-isconnectedlwith a. common wire41=leadingtothe sending apparat-us, and said armature is adapted when attracted to engage. the member .42 of a- V pairof normally closedsprings 42, 43, includediin the strand 8. of theconnecting cirbeing connected with the portionof the con-i ductor 8 leading to' theoflice ls'elector." In like manner, the armature .40- i'sdconneeted;

ingapparatus, said ai'ihature being adapted toengage'th'emember 450i a pair of'spring'sf 45, 46, which. are :normally' included. in} the.

.rin g Lst'randL-Q of.- the connecting circuit, to! 1, separate. said springs, jthe springli 45-ibeing.

connected with the portiomofthe stranddii: leading to the oflice selector. Armatures; 85),: 40 therefore, intheir attractive. movements-5. connect 'the .strandsQB, '9 of the, connecting: ,41,.-44 leading tot" the sendingap aratus. u -a 5,41, .Th'e-relay 26 "Fig: .5, in operating attracts itsarmature 47, which separates thefsprings'tl 24, 25 included in conductor 22,- sai'd ,aifma-- ture 4 en" aging the spring 25. which7i's Icon,- negted: w it r',tl1e-free"-pole of f grounded g' battery Q'Z'm IT-he armature 47.is;connected with aa feed wire 48..which supplies battery to the mechanismgiof, the sendin apparatus, andalso to a'lamp signal 49, w ichremains dis- Jilay'edwhilethe,sending'agoparatus is in use:' ,he-retalnlng magnets o :the sending ap paratus are permanently connected with the feedawire- 48, and are operated the instant 1battery ,}is applied by relay 26' to tl1e-feed circuit. a

Operation of the idfiz'cc lseleo tori- -The of ,fice selector, Fig.- 2, is provided with'fa shaft v72, through the win 50 arranged to have two movementsa rotary movement to select agroup of trunk lines leading to a particular ollice, or as m the present case, a group of trunk lines leadin to trunk selectors adapted to select an idle inter-office trunk, and a longitudinal or .11 Ward movement to select the first idle trun line of such group. The shaft carries three brushes, 51, 52,-53,'brushes 51 and52 being connected with the strands 8, 9 of the connecting circuit, and-the brush 53being the local-brush. The shaft 50 is adapted to be rotated-,byime'ans of. the magnet 54. and mechanism controlledvthereby, and to bemoved upward by'a magnet 55 and its asso- I eiated.appa1atus.'=iThe relay 30,- Fig.1,-

when operated, as before described, serves to place the ofliceselector in condition for operation. The armature56 of relay 30- is eonne'cted'with the conductor 57 which leads :from conductor 35 and battery-'17 through a winding of relay 30, armature 56 and its contactof'saidrela ,contaet springs 58, 59 .of relayl-60 to t e' oilice selector, and

thence through-the winding ofairelay 61 and througha-pair of'contacts 62..closed by" the shaft =50 when In normal position, to

earth. A circuit for'relay 61 is thereby provide d:bywayofconductors 18, 35,57; The said'rrelay 61 whengenergized attracts itsl {armatures .63, 64 and 65;-- the armature 63 being connectedywithr earth and when at The traotedcompleting -a-.-'locking'circuit for the relay- -61". independentfof contacts (52. armature- 65 isconnected' with the free poleof a 'igrounded batteryI G'Y, saidar'mature" when. attracted engaging its front :c'ontact wh ch-1s connected witha conductor 68..leading to earthzthroug h the winding of; thIere armature 64 of'said rela'y'is connectedwith met {or this armature. 'is"eonneeted with a conductor 60 which rleads through the contact-'spr1ngsw70, -71 associated with relay (iing-ofrelay :73 to earth. Relay 78 is provided withtwo: armatures 74,175, which withtheirbaek contacts are; normally lncluded' inthe stra'nds*'8, 9, of the? connecting eircuitpthe armatures being connected d1rectly"\vith the portions of the. strandsleading' to'the plug 7. The armatureI74 is adapted when attractedtoengage a front-contact which is connected with the conductor .76 leading through the vrotary stepping magnet 54 of the shaft 50, through the contact-springs 77, 78, associated with relay 72, to earth. The armature 75=of relay '73 when attracted isadapted to engage a front contact connccted-witha conductor 49 which leads through the armature and front contact of retaining magnet'66,-relay 72, to earth. The o'flice selector is now in condition for operation.

Turning now to the sending apparatus, I

loo

' selects-a trunk line which leadsto an idle trunkselector, said" selector: thereupon: 0perating to pick out an idle trunk line lead ing to thedesired'ofiice I will assume that the line L of the party with whomconversation is desired:ter'1ninates=at'oflice-B, andthat his-number at saidofiice is'1132. The

operator, therefore, after "listening in to as certain the number" ofthe' line desired do presses the office key B, key Iofrthe .t cu

sands keys,'key I of the hundreds keys, -key III of the tens keys and key II of the units-' keys.

.The oifice' controller, F

known as the office ieys. Each fkey coin prises a 'lunger adapted when de ressed-to carry a latch member, preferab y-conical in form, adapted when the lunger is depressedto enga'ge the undersi e of. a latch bar to lock the p'lungerin its de ressed POSltlDnd said plunger, when the late bar is operate by magnet SO-being restored by a suitable spring. Each of'said keys, when depressed,

forces into electrical contact springs 82,183- 84. Thes ring 82 of each key. is:c onnected with the free'pole of battery. 27.... The'sprin .83 is connected with a conductor 85 whic leads to a terminal of a bank of contacts 86 adapted toflbe' engaged by' the contact -arm 87.' Said arm is provided with a steppingmag Isaid*contactarm beingoper'ated by currentfrom" net- 88, the retainingmagnet 89 o the feed .wire' 48, as previously described.

Said 'contact arm 87- is connected with a*con--' ductor 90 whichwleads. to -earth through winding ,92of relay 91,-

'Thethird spring 84 through'the. winding of relayE-94, springs .95, 00, associated therewith,..to the ground contact ofa ygulsato r 97fsaid contact being arranged to the contact of. said attery,spring being connected with a conductor 101 leading to tact of relay 01," through the'armature- 105 and back contact'ofsluggish relay-106 to 'common- .wire 41; I:

dig-7, is providedwith a series-of keysf A, ,"etc., wh1ch are.

)elocke in suchposition-undert e controlof a release magnet 80.- Each lungerimay eed wire 48 previously" referred. to,.which is connected by relay 26'with the 4 eintermittently engaged bythe grounded-spring 98 of said pulsator.' The sprin 09 of said pulsator isconnectedwith-the reepole of grounded battery-100,-

et-88 of" -Assume now-that key B has been operatedzlCurrent will flow from the feed wire 48 b way of springs 82, 83', to the contact 86 in the bank. 86. Battery will also be applied from the feed wire through the springs 82, 83,- 84, toconductor 93 and thence through winding of relay 94, springs 95, 96, of said relay to earth by way of the pulsator when spring 98 thereof engages its contact. When such" contact is made, relay 94' isenergizedto attract its armatures 102, 107 Armature 107 is connected to earth and engages-contactspring 95, separating the same from its anvil 96 and completm a locking circuit for relay 94 from the cedwire independent of the pulsator." Armature 102 in its attracted position connects the. battery contact of the pulsator with I strand 8, armature 74 of-relay .73 of the oilice selector; Fig. 2, conductor 76, through the stepping magnet 54 of the selector, springs 77. 78 of-relay 72 to earth.

The pulsator -97, "as i already described,

when in position to 'closcits grounded contactcompletes a circuit for the relay '94 which connects the-battery contact of the pulsator to the stepping magnets. This provision is made so that the first impulse applied to thestepping :magnets will be a full one, that is, when the pulsator is engaging its ground contact it completesthe circuit for relay 94, so that when it engages its battery contact the circuit for the stepping magnet will be ready to receive the complete im ulse.

The step mg magnets 88, 54, respond together'to tie pulsating current and rotate thecontact-arm 87 of the controller and the shaft 150 of the selector, respectively. When the contact arm 87 of the 'oilice controller of each key is'conr n'ectedywith a conductor 98 -which .lads

reaches'th'econtaet point 86, which is connected through the keyB withthe feedwire,".=and the shaft ISO-has been ste ped around so-as to bring its brushes in rent of (the group of terminals leading'to trunk selectors adapted to pick out trunklines leading to the desired office. eurrent'flows' 'connecteddirectly to cart Thearmature 108 therefore -when attracted I completes a locking circuit for relay 91, and also the circuit of the sluggish relay 106.

A conductor 111- extends from conductor 90 between the arm 87 .and relay 91 to the back contact of armature 112 of sluggish relay 106, said armature 112- being connected with common=wire 44, and when the arm 87 reaches thepoint 86-at which battery is present, an impulse-is delivered before the relaylOG-has had time to-operate,

to conductor 44, from the feed wire, byway of key B, conductors 85, 90 and 111'and the armature 112 and back contact of relay':106.

. This impulse passes through the armature 40 and its contact 'of relay 31, Fig. 1, strand 9 of the c'onnectingcirouit: to the ofiice selector, thence through-armature 75 of relay 73 andits front contact to-conductor 79, armature and front contaotof retaining magnet 66, winding of relay 72 to earth. Relay 72 is thereupon operated and attracts its armatures 113, 114, 115':"-" The armature 114is connected with conductor 79 and is adapted when attractedto engage a contact connected with the conductor 69 which leads to the free ole of battery 67, thereby completing a 100 ring circuit for the relay 72 from the freepole of battery-'67,

armature'64 of rolay-6 conductor'69- to earth byway of armature 114 and; cond1ictor79. a

The armature 113 of relay 72.is connected withaconductor 1'16 WhlClI leads to the front contact of armature 117lofrelay 73',

said armature 117 being connected with-a -72 when-attracted enga es the spring 71 through relay 73, and connects said relay 73 through its own armature-117-=and:front contact with the local brush'53, for-a purpose to belater explained. K l I The armature 115 of relay 72 when attracted engages contact spring 78 which'is grounded, and separates the same; from sprin '77 thereby 'o ening the branch' 76 g i P magnet 54; Said I containing the steppm armature is connecte with a conductor which leads through the-=li fting magnet 55 of the-selector, armature 120 and'fr'ont contact of relay 73, to the battery contactof a pulsator-='121.-' The shaft now begins its u ward hunt for a trunk line-leadingflto an i' le selector' adapted to'flpiclt out any idle trunk line leading to the o c'e B. Ifthe first trunk line is'busyybattery will be resent upon its lOcaF-terminal 122, and wil --maintain relay 73 excited in the-'path'provided byway of conductor "118, armature 117 of said relay 'and its front contact, conductor .116, armature 113 and front'contact of relay 72,-conductor 69'to earth; the armature 120 of sad relay 73 while attracted maintains to the local'brush 53 the circuit of the step ing magnet 55. -When brushes: on'the shaft 50,"there will be no potential present at the local termlnal 122 thereof, and the relay 73will be deprived of current, and will releaselall its armatures; armature 120 opening the circuit of the l fting magnet 55; armatures 74, 75, restoring the continuity of the strands 8, 9 of the connecting circuit; and the armature 117 breaking the connection of relay 73 with the local brush 53, and connecting at its back contact conductor 118,1eadin from said brush, with a conductor 123 -lea ingto conductor 69, which is connected b armature 64 of relay 61 with the free p0 e of battery 67. The

brushes 51, 52, 53,1 of shaft 50, now rest in engagement wit contact terminals 124, 125,122 respectively, connected with a trunk line leading to a trunk selector.

'The lowermost set of terminals 122, 125, 124, aswellas-the sets above in each of the vertical rows fpreferably form stopping points for the o co selector arm and lead to automatic trunkselectors. The oilice selector takes one rotary step before engaging the first connected set.

I 1 Operation of trunk seZe0tor.The,. trunk selector-comprises a shaft 126 'havingone 1novement-,-'-a rotary mov'ement,--said shaft being rovided with a steppin magnet 127. The -s 'aftcarries thredbrusl y me 128,129, 130,- the=brushes 128, 129,'being linebrushes connected by conductors 131, 132, with the contact terminals 124, 1250f the selector, the

the relay 73 has restored its armatu'res, as

reviously described, whereupon the relay 35 and reta ning magnet 138 are operated. The retammg magnet 138 in operatin attracts its armature and completes 11 10c ring circuit for itself independent of contacts 139 through "its" own] armature, resistance 138 and ground, the function of this resistance being to revent the short-circuiting of relay 135'. e'lay 135 in operating attracts its armatures 133, 134, 141 and 147. The armatures133', 134 whenattracted, maintain the selector brushes 128, 129 dead during the selection? Thdarmatur'e 141 is connected witha conductor 142 which leads through the w1nd1ng143- of'relay 135 to earth. Said armature141 in" itsattractcd position engages .th'e contact-spring 144, and se arates the same from its normal contact 1 5, said spring 144 beingconnected with a conductor 146 leading to the local brush 130 upon the selectorarm. Thezarmature 147 is connected with a conductor148 which-leads to the battery contact cf the pulsator149, while the front contact'of said armature is connected with conductor.150- leading through. the winding of vth'e'stepping magnet 127 of the trunk selector to earth.-- Thus when relay 135 is operated. a circuit-is completed by armature 147, by-way of conductors-148, 150, said circuit including the magnet 127, which is oJeratedto advance the,test1brushw130 on s aft 126 one step, to the terminalsof a trunk line leading to the desired oflice. If this trunk line is busy, battery will be. pres.- ent at the local terminal 151 of such.line, and current will flow through thelocalbrush 130, conductor 146, spring 144 andarmature 141, conductor 142, winding 143 of relay 135 to earth, maintaining the relay 135 energized. The stepping magnet127 will; thus continue to receive current and will advance the brush another step, and so onuntil an vent disturbances; opening at-armature147 the circuit of the -stepping magnete'127f; and breaking at armaturev 141 theconnection-of relay 135 with the local brush 130.. Sprin 145, which now rests inen agement witi spring 144, is connected wit a conductor 152 leading-to conductor 137, which is con,- nected withbattery 67 at the oflice selector, and a ctential is thereby applied by way of con uctors 69, 123,118, 137, 152, 146 to the contact terminal 151 of the trunk-line upon which the selector brush 130 rests, to lock out other trunk selectors from the trunk line selected. The brushes 128, 129 of the trunk selector now rest upon the terminals of the limbs 152, 153, respectively. of a twowire trunk line leading to the ofiice B and the primary selector forming the terminal of such trunk line at the said distant oflice.

Operation of translating machine and prima-m saZeetmn-As before stated, the line with which connection isdesired, is numbered 1132. Therefore the operator. de-v presses key I of the 1000s. ke s; 154, key of the 100s keys 155,. key II ofthe 10s keys.156, and key II of the units keys 157. 'ljhe 1000s and 100s keys control theoperation of the translator shown at thezlcft in F155. 6 wh ch operates the primary selector 1d ,lihg. 8," forming the.terminal of the trunkhne at the distant oflice to connect the trunk lines w than idleconnector ot-the group. containing, theldesired number. The shat159 of. the translator is arranged to i by; brush. 164, andthe have two movements, one in long step under the control of stepping magnet 160, and the other in short ste under the control of magnet 161. The sha t carries three brushes, the brush 162 being adapted to cooperate withthede ressed 1000s and 100s keys, and the ban: of contacts 163, to stop the shaft at the proper point to cause the rush 164' of the translator to apply battery to a particular'contact of the primary. controller 165,- andtcause the same to operate in series with the primary selector until the contact arm 166-: of the primary controller reaches the contact to which battery has been applied rimar selector reaches the roup of trun s leading to the connectors o the group wherein is located the called partys line, at which time the prima' controller and primary selector are steppe andthe primary selector caused to locate an idle connector. The third brush 167 of the translator is-provided with a bank of contacts 168, which control the applicationof battery to-a predetermined oint uponthe auxiliary controller 169, which is operated after the primary selector has located the connector to advance the brushes of such connector into the proper bank of its threebanks of 100 lines each.

Describing now more in detail the operation ofthe translating mechanism and'primaryj'selectors: The relays 511 and 172, Fig. 7,'control the starting of the translating mechanism, said relays being arranged to operate-when the trunk selector has made connection with an idle trunk line leading to a distant station. Said relay 511. isincludeddn a conductor 170lcadin from the front contact ofthe armature 05 of the relay 106,through' contact springs-171 control ed by the armature 173 of relay 172, to the feed wire 48, the connection of this conductor at armature 105 of relay 106 with wire 41 being completed when the slu gish relay 106 is operated after the impu se is app 163C150 wire 44 to start the ofrice selector in its upward hunt for an idle trunk selector. The-circuit-.for rela .511 extends from the feed wire 48lthroug conductor 170 to conductor-41, thence-through. contacts 39, 42 of rela 31,; to link conductor 8, over trunk wire 1 1 to'the trunk selector, through the contacts-closed thereby, to trunk; wire 152 leading to the distant office, where the same pa sses through onewinding of a repeating coil bridged across the trunk conductors to a conductor 174, which leads through the winding of relay 175, normally closed contacts 176, 177 of a polarized relay 178, normally closed contacts-179, 180, of said relay, normally closed contacts 181, 182 of relay 183, to trunk conductor 153, and thence to the prlmary selector, through the armature 184 and-backcontact of relay 185, to a conductor 186 "which leads through contact "ture 204 completi'n 20.5 by. way of 'con uctor 206,.through the springs 187closed by the shaft of the selector while in normal position.

The'relays 511 and 172 of the sending apparatus, Fig. 7, are sluggish 1n the1r operation to provide a time interval wherein the primary selector may get into condition for operation.- This is accomplished underthe control of the rela 175 associatedfwith the trunk line at the. istant oifice, which is in the circuit just traced for the relay: 511-.

Said relay 175 in' attracting,its-{armature com letes a circuit for, battery l8 9-byvway'of con uctor 190 which leads through the nor mallyv closed contact springs 191, 192 of relay 193, winding-of relay 193,"winding, of

the retaining n1agnet 194'of".the primary sclectorto, earth, throughthe contact springs closed b' the shaft195 of the, primaryselector w ien in normal conditiom: Therelay 193 and'retainingmagnet. 194 are now energized and a locking circuit is completedfor said relay andmagnet independent of relay 175, said circuit extending from the free pole of grounded battery 196, conductor 188, through the contact sprm s 197, 198 of relay 183, armature 199 0 re ay .193- (which is now in engagement with the contact sprin 191, separating the same from its norma contact 192, and disconnecting battery 189 from the circuit reviously traced therefor) through the win ing of t e retaining magnet and its armature 200 and front, contact to earth. The armature 201 ofv relay-193, which is connected with the vportion of con ductor 19,0 leadingto the front contact of the armaturc of relay 175, in its attracted position opens the contact springs 202 which. arehnornzally included in the-trunk con-' ductor 152, and engagesthe member thereof which is ecnneetearwith the-gportion of trunk conductor .152 leading directly to the primary selector, the contacts 202 being included in said. conductor between the repeating coil and the selector. 7 The repeatingcoil serves to maintain the inductive cont nuity "of. the trunk circuit while maintaining the, circuit broken for direct current; e two Windings-of-the repeatin coil connectedgwith;the Eportion of the trun c-circuit' leading back'to the trunk selector'qare included in a bridge ofsaid trunk conductor ,avith a eondenser,while the other two windin s of .the repeating .coi1 which areinclude in the portion 'of the' trunk r'circuitglading to the selector, are connected .in'ia bridge-of the trunk circuit with a grounded :battery 208. I a The retainin .magnet 194when energized as'previously' escr1bed,:attracts its armaa'"eircuit from battery contact springs 207,208 ofrelay 209, winding of relay 1 8 5 to carth, saidrelay thereupon attracting its armatures 210, 184, 211 and 212.

The armature 210 of relay 185, which with its back contact is normally included in the trunk conductor 152, when attracted engages a front contact connected with the conductor 1213 leading through the stepping magnet 214 of the primary selector contact spr ngs 215 of relay 209 to earth. The magnet 214 is arranged to rotate the shaft 195' in,84 steps to pick out the group of trunk lines leading to connectors serving a particular group of 800 lines. The remaining armatures-of the relay 185 bring-"into operative condition apparatus which will be hereinafter described.

The primary selector is now incondition for operation, and sluggish relay 511 of the sending apparatus, Fig. 7, has now operated to energize'rela 172, whichin turncauses the de'cinergization of relay 511, said relay 172 locking itself up, and the combination of relays 511 and 17 2, with the first-mentioned rela .inert and the other energized,

starts t e translating mechanism.- Relay 511 is provided with an armature 216 connected with the feed wire 48, said armature when attracted, completing a circuit for the relay 172. Relay 172, which is also sluggish, attracts its armature 173, opening the contacts 171,-- which are included in the circuit of the relay 511, and by means of said armature 173 and one'of the members of the contacts 171,- locking itself. to earth, from the feed wire. The armature 216 of relay 511, which is connected with the feed wire is provided with a back contact connected with a conductor 217 leading through the armature 218 and its front contact. of relay 172, to the 1000s keys, and when armature 216 of relay. 511 is retracted and armature 218 of relay 172 is attracted, current flows from the feed wire over the conductor 217, through the armature 219 and back contact of relay 220 to the 1000skeys 154, Fig. 6.

Each 1000s key, whenoperated, is arran' ed to be locked in its depressed position un er the control of a*release magnet. 221, as described in connection with the oilice controller; each key-when depressed forcing into electrical engagement contact springs 222, 223 and 224. Contact spring 222 is connected withgth'e conductor 217 which is united by the feed wire-48 to the free pole of batteryt27, and said spring in. engaging its anvil 223 aplplies battery to' a thousands contact termina in the bank-103 over which the brush1162 of thejtranslator sweeps. In the present case -scalling line 1132'since key I is depressed, battery will be applied toathe second thousands contact point 225 of the bank 163. It willbe understood that.

thereby with battery '27, is connected with a I conductor 226'-whicl1' extends from'all the springs 224'of the IOOOs'keys, through the winding of relay 227,- contact springs-p228, associated'therewith, to the ground contact of-a pulsa'tor 229;: and whenthe'groun'd spring of'the pulsator engages 'saidizcontact a circuit is completed for relay'227' wh1ch draws up its grounded armature 230, said armature engaging the member" of sprmgs 228 connects withthe winding of relay 2 7 and completing a' lo'ckin g circuit for said relay independent of the 'pulsator,

The relay 227' is arranged to start the operation of stepping magnet 160- of t e translator, said relay having an armature 231, which, when attracted, com l'etes, the continuity of a conductor 232 lea mg from the battery contact of a; pulsator 233, through the winding of relay 234, armature 235 and back contact of relay 236 to the con ductor'41,'which is connected with the tip strand=-of the connecting circuit, and on through to the rimary selecton- It will be noted that the ocking circuit for relay-227 is established by the pulsator 229 when in engagement'wit 1 its ground contact so that the OII'GiIlt'Of COTIdUCtOI 232'wille completed before the pulsator 233 engages its attery-contact, thus insuring 'a' complete initial im ulse over conductor 282.-

When'tie battery spring of the pulsator 233 engages its contact, current flowsover conductor 232 through the relay 234, over conductor 41', tipstrand 8, trunk-conductors 131,152 through one winding of there.- peatin coil" to conductor 17 4, thence through relay-1 5, contacts of-relays 178 and183, to trunk conductor 153, through the armature 184,'a nd front contact ofrelay 185, to conductor 237," through contacts 2380f relay 209.to e'arth through-the winding of said relay, thiscurrent being-withoutetfeet' u on said relay} 209. Relay= 175 inthe circuit ust traced, respondstoasald current, and'inattractingits armature applies current-from batteryi-189 to-conductor 100, andthenc'e through armature"201 and" one: of' the membe'rs of springs-202of relayaitiigto trunk conductor 1 52, thence'through 'ar ature 210 andits front;contact'otrelay 185; conductor 218, rotary steppingmagnet m' ofthe shaft 1915,; contact springs 215 of relay 209to earth, whereupon the stepping magnet 21+ isoperated to rotate the shaft 195 one step. This advance of the rimary selector 1s sunply to save time in t e operation of the system.

The relay 234 in the circuit traced from the pulsator 233 responds to the pulsations battery to aconductor242 which leads to earth through the-stepping magnet'243 of the primary controller 165 to advance the arm 166 thereof, It will thus be seen that the translator arm, the contact arm of the primary controller, and the arm of the primary selector, advance together until the brush 162' of the translator reaches the thousands oint 225 of the bank 163 of contacts, at w ich time each of said arms will have taken three steps-the translator arm three long steps and the primary controller and primary selector arms three short steps such The holdin or retaining ma nets of the translator an "primary centre ler are permanently connected with the feed wire and were operated the instant relay 26 a plied battery to the feed wire, when tie sending apparatus was taken by the connectin circuit for use.

l/Vhen the brush 162 of the translator reaches the contact 225 it finds current thereon, and said current passes throu h the brush 162 to a conductor 244, whic leads throu lr the armature 245 and back contact of re ay-220, through the winding 246 of relay 236 toearth, operating'said relay 236, which 0 tons at its armature 235 and back contact t e'conductor 282and the circuit before traced including the relay 284, pulsato'r 233,-an the relay'175'at' the primary selector,'so'stopping-' the movement of the arms of the'transla-tor, primary controller and primary selector. i

The'translator is now ready to respond to the control of the 100s keysand seek the intermed ate gmint beyond the contact 225 where'it 1s esired to finally stop the translator; In the present case, since he I of the 100s keys is depressed the secon intermediate" point beyond point 225 would be 'supphedwith battery in the following mannected througlr-a" winding of relay 286 to earth; and-alien said arma'ture247 is attracted, a circuit is completed for the relay key 155.

through t zfinlike manner wou vate listo enga e thirty-tour terminals.,, From ,c'aci termma ,of .the "rnnary controller a translator has been brought to a 220,-which attracts its armature 219, 245.

Armature 219 when attracted connects conductor217 and battery 27 with conductor 249,1eadin to the springs 250 of the 100s he armature 245 of relay 220 in its attractive movement connects conductor :24-4. leading from brush 162 with a conductor251 leading through the winding of the relay 252 to earth. Brush 162 is now dead.

since battery is reinoyed by armature 219 of -to the-second intermediate contact beyon point 225. The third spring 253, applies current by way of the springs 250, 512 and conductors 249, 217, to conductor 254 leadiug through winding of relay 255, to earth; said relay 255 in attracting. its armature completing the continuity of a circuit513 which extends from the battery contact of a pulsator 257, through the winding of the short ste magnet 161 of the translator,

he armature 258 and back contact of relay 252 to earth. The pulsator 257 applies current through the circuit just traced tooperate the stepping magnet 161 and advance the shaft in two short,steps', 'until the brush 162 of the translator rests upon the second intermediatepoint be end a contact 225, at which time current will flow-by way "of. brush 162 and conductor 244, through the farmatu're .245, and front contact of relay 220, conductor 251, to'earththrough relay 252 which will attract its armature 258 and open the circuit of the pulsator 257 and the stepping ma net 161 of the translator, leaving the sha t of the translator, three lon steps and two short'steps from its norma position.

, Primary .-contr0Zler.-Theprimar controller in an exchange such as-I am escribing,,\ifherethe lines are arranged in groups oi? 300, would have thirty-four contact points,. each point representin a group contact point of a gummy se ector, which 1 have thirty-four rotary conductor runs .-.to .-t reecontactpoints stra liiped to ether, over which the second brus 1640 ,the, translator is arranged to sweep, smcbbrushbeing, adapted after the M I I redetermined oint under the control of t e 1000s and 19 s keys, to applyflbat'tory'to a certain groupof stra ped contacts to stopthecontroller and,se ector whejn the selector is, advanced to the group of trunk lines leading to the connectors fseryin g the group of ;lines f it- 1 19231 6 e la irerfi s 111w s t' of t e translator.

It should be rememhere The operation of the primary controller and selector is automatically effected immediatel upon the com' lotion of the movement he relay 252, which was operated the instant the translator brush 162 landed on the second intermediate oint, in attracting its armature 262, applie current 'from the positive batter 263 to conductor 264 leading to the brus 164, which now rests upon the set of strapped contacts connected with the fourth contact 265 in the bank of contacts of the rimary controller. at this point that the primar controller and rimary selector followed t e long steps 0 the translator brush, so that'the arm 166 of the primary controller and the brushes on the shaft 195 of the primary selector now rest on their third group terminals. This arrangement is simply to save time in setting up the connection.

The armature 266 of relay 252, which was operated when the translator completed its movement, serves to start the primary controller and selector, said armature 266 bein connectedwith aground contact of the pn sator 267, the front contact of said armature being connected with a conductor 268- leading through contacts 269 and the relay 270 to the feed wire 48. ,The instant theground spring of the pulsator 267 engages-its contact, a circuit is. completed from battery 27 over the feed wire 48,- conductor 268, through relay 270, armature 266 and front "contact of relay 252, to earth; and the relay 270-in operating attracts its armature 271, which separates springs 269, engaging one'of such springsto complete a locking circuit of such relay 270,,from the feed wire independent of the pulsator.

An armature 272 is provided forrelay .270, which is connected with the battery contact of a pulsator .278, the front contact of armature 272 being connected with a conductor 274 leading through arelay 275, armature 276 and back contact of relay 277, to conductor 41, which leads to the tip strand 8. Relay 275 controlsa circuit from battery 278 through the stepping magnet 243 of the controller' The pulsator 273 applies current through the relay 275 and out over conductor 41, tip strand 8,; trunk conductors .131, 152, to-the distantoflice, and thence through conductor 174, relay 175, contacts ,181, 182 of relay 183to. trunk conductor .193, and one of the. springs 202 to the trunk conductor 152, thence through the armature 210 of relay-185. conductor 213, stepping magnet 214 of the primary selector, consprings 285,. 286, windin has 215-of'relay 9 to earth. The relay fromsaid battery throughthe arm 166 of the controller and the conductor 269,- leadin from said arm through a winding of iei ay 277,-to earth. Relay 277 now operates and attracts its armature 276, opening the circuit from the pulsator 273 through the relay 2750f the primary controller and the relay at the distant station, said relay 17 5 controlling the circuit through the stepping magnet 214 of the primary selector. Said relay 277 also-draws up its armature 280, completing-a locking circuit for itself which extends from the feed wire 48 through sluggish relay 281, winding of relay 277 to earth. The brushes on the "shaft 195 of the primary'selector have now reached the fourth group-of trunk lines, which lead to connectors adapted to reach the line with which conversation is desired.

Automatic selection of idle trunk 53 se- Z80tor.--The attraction 'of armature 276" of relay 277' completed the-continuity of a conductor 282 which leads from the conductor 269 between thebrush 166' and relay 277, throughthearma'ture276 and front'contact of relay 277;armature 283' and back contact of'sluggish relay 281, to-conductor 44, and before the sluggish relay281 has had time to operate, animpulse from positivebatter 268 flows by way'of conductor 264,b1l151 164, contact arm106, and its fourth terminal, conductors 269, and 282, conductor 44, to the ring strand 9 of the connecting circuit, trunk cond1'1'ctors""132,158, through a lower windinglof therepeatin coil, to conductor 284,-"w ich leads throug 1" the contact of the polarized relay 178*t0 earth- "ySai ositive current 'cau'se's the relay 178. to ti (2' its armature in q contra-clockwise-direction, whereupon spring 177 ofsaid 'relay is-separated from its anv1l-176 and thrown intoflenga ement withfacontac't 287;,connectedwitht e free 'pole' of grounded battery 288 current thereupon f fiowing' froiwbattery "288 through the sprm' 287',"177,conductor 174', contacts 181, .1820 relay 188, trunk conductor 158,-'armature"1 84=andfro nt contact of re'lay185, co'nductorf'287"spr1ngs, 288 'ofrelay 200, and

*winding' o said relay tc earth; Relay 209 'is' now'ene'r'gized and drawsup its armatures 289,290, 291,,- 'The armature 290is connect- Jedw1tli'conductor'206 wlii'clilead am the battery'205tand said armature when attracted se arates springs 238, engagmg the member tiereof leading directly to earth through the relay 209' and completing a lockin clrcuit for said relay independent of re ay 178, which by this time has beendeprived of current, owing to the operation of the sluggish relay 281. Armature 291 of relay 209 is connectedwith a conductor 292 leading through the lifting magnet 293 of the primary se cctor, armature 212 and front contact of relay to the battery contact of a pulsator 294. And said armature 291 when attracted is adapted to separate s rings 215, breaking the continuity of conuctor 218 connecting the rotary stepping magnet 214 with trunk conductor 152, and to engage the grounded contact spring of said air of sfprings 215 to complete a circuit or the li ing magnet 293 and the m1- sator 294. Said magnet293 is adapte to step the shaft u in search of a trunk line leading to an id e connector adapted to serve the fourth grou of three hundred lines in which the line esired, number 1132, is to be found.

'The armature 289 of relay 209 is connected with a conductor 296 leading through the armature 211 and front contact of relay 185 to the local brush 297 of the primary selector; said armature 289 whenattractcd is adapted to'separate springs 207,208 included in .t e circuit from battery, 205, with relay 185,I and to engage the spring 208, which leads [directly to earth'through relay 185, thereby connecting said relay 185 through its own armature 211 and front contact with said local brush 297. Now when the selector has been given one upward movement to brin its brushes into en agemcnt with the terminals of a trunk line' eading to the first connector of the fourth group if that conmotor is busy, the local brus 297 of the trunlr line leading to said connector will have potential thcreon'from'the local ter-' minal 2980f such trunk, and current will flow through the local brush 297, conductor i296, armature 211 and front contact of relay 185,'win ding of relay 185 to earth, maintainin relay'185energ1zed. Relay 185 in turn w lfmamtain the circuit of the up-stepping ma et 2 93 intact, and the said magnet 293 Wll 11ftthe shaft 195 another step, and so on until a'trunlr line leading to an idle con- 'nector is'reached, whenjno current will be found upon the local terminal 298 of such line, and relay 185 will. be deprived of current, releasing its armatures. 'The armatures 210 184 in retracting restore the contlnuity o the trunk conductors 152 153; the armature 212 opens the circuit of the upmagnc 293, and the armature 211 opens t e connection of rela 185 with the local brush 297, and engages its back contact connected with a conductor 299 which leads T local brush 297 a test potential upon the multiples of the local trunk terminal 298.

The line brushes of the shaft 195, which form the terminals of trunk conductors 152, 153, are now in en agement withtermmals of the trunk lino leading. to anidle c0n nector adapted to I reach-line 1132, said "brushes engaging terminals connected with conductors 300, 301, respectively, while the localbrush 297,.which is connected with the free pole ofb'attcry 205, up )lies battery by way of terminal 298, to the. coal trunk conductor 302 which leads through the contact springs 303, 30-1 of a busy test and lockout relay 305 of the selected connector, Fig. 4,, through the winding of the retaining magnet 306 of. the connector, contact springs.

closed by the shaft ofthe connector when in its normal position, to earth.. The retaining magnet 306 thereupon attracts1ts arma- "turcs 307", 308, armature 307 completing a locking circuit for the retainingmagnet 306, inde endent of the springs which are separate while the connector shaft is away from normal position.

If the line with. which connection is to be established had been a line terminating in theoffice where the call originated, it is apparent that no inter-oflice trunk would be needed in; establishing. the connection. .Instead the trunk selector would. pick out a trunk line the local oilice leading to a primary selector in such oflice, which would select a connector adaptedto reachthe line desired. In Fig. 11, we have shown such trunlg-line and selector. The trunk selector, Fig, 2,,fwould be operated to .bring its brushes 128, 120,. and 130 into engagement with the.;-to rminals.of an idle three-wire trunk, comprising conductorsv 514,; 515 and 516 leading; to the primary selector, 517 in exchangcQA. After the trunk-selector had completed connection withthe three-wire trunk, current would beaapplied from the localbattcryB? of. the office selector to the brush 130 of the trunk selector, and to the local. wire 516 of the three-wire trunk-said conductor v516 leading directly through the retaining magnet 518 oftho'primary sclcetor, contact springs closed by the shaft of,thc,selcctor when in normal position, to earth, said retaining magnet attracting its armature 51.0 ;to complete a lockingcircuit, .,,f or', 1 tself independent," of said- .-cont'act springs. The'armature 520 of the retaining magnet is. connected. with the free pole of "a' grounded battery, and is adapted in ,.it's attractiye movement to engagea. contact eon- ,nected.witlmqoi ductor .521 loadin g through contaetsprings.522 of a relay .523, winding of a', rclay"52 4, toearth Theyrelay152lais .nowpeperated, and'httractsfits"arriiatures me,

526, 527 and 528. The armature and back contact of the relay524 arenormally included in the trunk conductor 514, and said armature when attracted is adapted to engage a contact connected with a conductor 529 which leads throughthe rotary stepping magnet 530 of the primary selector, contact s rings 531 controlled by relay523, to earth. The armature 526 of said relay 524,- which, with its backcontact, is normally included in-the trunk conductor 515, is adaptedwhen attracted to engage a front contact con- .nected with. a conductor 532' which leads through the, normally closed contact springs 533 of relay 523, and :the winding of said relay to earth. The armatures 527, 528 bring into operative condition apparatus to be described hereafter. The primary selecselector to earth, suchcurrent being without effect 11 on said magnet. Itshould be stated at this point that the primary selector under consideration is very similar to the primary selector associated with the two-. wire trunk, that'is, it is rovided with a shaft adapted to be steppe around to pick out a group of trunk lines leading .to connectorsadapted to reach a given group of 300 subscribers. Said shaft is then arranged tostepupwardly to pick out an idle.trunk lineofthe group leading to a connector.

. .lVhen the starting mechanism is-operated, and its. brush 162 is seeking theterminal which has been supplied with battery by the thousands key, impulses are sent. over the trunk conductor 514, to give the brushes of the selector. anumher of rotary' steps corresponding to the long steps of the translator, as described in connection with the two-wire trunk and its selector, and when the translator has stopped, the primary controller .operates, and impulses are again delivered relay 523. scparates'springs, 522 and engages the .member-thereof connecte(l.(lirectly to earth through relay 524, so connectin said relay through its-ownarmaturo 52? and ,front contact withtho local brush of the sc1ector..., .Thearmature 5365f said relay 

